Hormone Replacement Therapy

The use of estrogen to supplement that which is no longer being produced by the body, and hormone therapy (HT), in which estrogen and progestin (a synthetic progesterone) are used in combination, have been the subject of great controversy over the years.

To learn more about women's health, and specifically hormone therapy, the National Heart, Lung, and Blood Institute of the National Institutes of Health (NIH) launched the Women's Health Initiative (WHI) in 1991. The study consisted of clinical trials and an observational study, which together involved more than 161,808 generally healthy postmenopausal women.

The clinical trials were designed to test the effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, and breast and colorectal cancer.

The hormone trial had two studies: the estrogen-plus-progestin study of women with a uterus and the estrogen-alone study of women without a uterus. Women with a uterus were given progestin in combination with estrogen, a practice known to prevent endometrial cancer. In both hormone therapy studies, women were randomly assigned to either the hormone medication being studied or to placebo (inactive substance). Compared with placebo, the estrogen plus progestin treatment resulted in:

Increased risk of heart attack

Increased risk of stroke

Increased risk of blood clots

Increased risk of breast cancer

Reduced risk of colorectal cancer

Fewer fractures

No protection against mild cognitive impairment and increased risk of dementia (study included only women 65 and older)

Compared with placebo, treatment with estrogen alone resulted in:

No difference in risk for heart attack

Increased risk of stroke

Increased risk of blood clots

Uncertain effect for breast cancer

No difference in risk for colorectal cancer

Reduced risk of fracture

Findings about memory and cognitive function are not yet available.

The WHI recommends that women follow the FDA advice on hormone (estrogen-alone or estrogen-plus-progestin) therapy. It states that hormone therapy should not be taken to prevent heart disease.

These products are approved therapies for relief from moderate to severe hot flashes and symptoms of vulvar and vaginal atrophy. Although hormone therapy may be effective for the prevention of postmenopausal osteoporosis, it should only be considered for women at significant risk of osteoporosis who cannot take non-estrogen medications. The FDA recommends that hormone therapy be used at the lowest doses for the shortest duration needed to achieve treatment goals. Postmenopausal women who use or are considering using hormone therapy should discuss the possible benefits and risks to them with their health care providers.

The National Heart, Lung, and Blood Institute offers the following suggestions for women who are deciding whether or not to use hormone therapy:

Because the study involved healthy women, only a small number of them had either a negative or positive effect from estrogen plus progestin therapy. The percentages describe what would happen to a whole population—not to an individual woman. In the estrogen plus progestin therapy study the increase risk of breast cancer was eight additional cases for every 10,000 women over one year; there was a 24 percent increase overall.

The most important thing a woman can do in deciding to continue hormone therapy is discuss the current research with her health care provider and health care team.

Women need to be aware that taking a combined progesterone and estrogen regimen or estrogen alone is no longer recommended to prevent heart disease. A woman should discuss other alternatives of protecting the heart with her health care provider.

Women should discuss with their health care providers the value of taking combined progesterone and estrogen therapy or estrogen to prevent osteoporosis. There may be alternative treatments based on a woman's unique health profile.

Always consult your health care provider for more information.

What is hormone therapy?

As a woman approaches menopause, the production of estrogen and progesterone fluctuates and then decreases significantly. Symptoms such as hot flashes often result from the changing hormone levels. After a woman's last menstrual period, when her ovaries make much less estrogen and progesterone, some symptoms might disappear, but others may continue.

To help relieve these symptoms, some women use hormones. This is called menopausal hormone therapy (MHT). This approach used to be called hormone replacement therapy or HRT. MHT describes several different hormone combinations available in a variety of forms and doses.

How is hormone therapy administered?

According to the American Medical Association, hormone therapy can be administered in a variety of methods, including the following:

estrogen pills

Estrogen pills can either be taken every day or for 25 days each month. Women who have had a hysterectomy can take estrogen alone, while those who have not may take a combination pill (estrogen and progestin).

estrogen/progestin pills

There are two methods—the continuous method and the cyclic method—for taking estrogen and progestin. In the continuous method, a pill that contains both estrogen and progestin is taken daily. Occasionally, irregular bleeding may occur.

The cyclic method involves taking estrogen and progestin separately - with estrogen taken either every day or daily for 25 days of the month and progestin taken for 10 to 14 days of the month. This may cause monthly "withdrawal" bleeding.

estrogen and estrogen/progestin skin patches

Using this method, a patch is applied to the skin of the abdomen or buttocks for 3 ½ or 7 days. The patch is then discarded and a new one is applied. The patch can be left on at all times, even while swimming or bathing, and either the estrogen, or estrogen/progestin combination is delivered through the skin into the bloodstream. Progestin can be taken in a pill form with the patch. The patches may cause monthly bleeding.

estrogen cream

Estrogen cream is inserted into the vagina or used locally around the vulva to help with vaginal dryness and urinary problems.

raloxifene

Raloxifene is an estrogen-like drug (sometimes called "designer estrogen") that is part of a new class of drugs called selective estrogen receptor modulators (SERMs).

For women who are appropriate candidates, this type of therapy can often be customized to provide the most benefits with the least side effects. It is important for women to talk with their health care providers about any discomfort or menstrual symptoms experienced with hormone treatment, as treatment approaches and dosages can be adjusted.